Generation of electron–positron pairs upon grazing incidence of a laser pulse on a foil

We study the generation of electron–positron pairs in the interaction of laser radiation with a flat overcritical target (foil). Using full-scale three-dimensional particle-in-cell simulation with account of quantum-electrodynamic (QED) effects, we determine the parameters of generated pairs such as total number, density and angular distribution. Two different interaction configurations are considered based on the focusing of six laser pulses (with parameters expected at XCELS laser facility) onto a solid target. The configurations are not optimal in terms of the parameters ultimately achievable at this facility but in turn are reliable and quite simple in terms of their practical feasibility. It is shown that even in these configurations it is possible to generate electron–positron pairs with energies up to GeV, a total number of pairs exceeding 10¹¹ and an average density reaching 2×10²⁰ cm^–3. Generating electron–positron plasma with such parameters opens possibilities of laboratory investigation of several astrophysical phenomena.